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Cannot maintain pool chemistry

I had some algae in my pool on Sunday, and began adding massive amounts of bleach to combat it. Since then (today is Wednesday) I have put in 25 gallons of bleach, all 6%. Currently my Ph is 7.4%, but chlorine levels appear to be 0%. Pool is blue but is very cloudy. I cannot see the bottom.

I have a 15,000 gallon gunite pool. I would like to get my chlorine levels up to 6%. Do I need to add more bleach per day? I cleaned my main filters (4 cartridge) on Sunday and again on Tuesday. They looked good Tuesday. My other filters do not show any algae at this time, but my pool sweep (Jandy Ray Vac) showed a little this morning.

My wife bought a bottle of "Algae Banish" from a pool supply store. I haven't used it yet. Do you think I should add this to the pool and see what the results are?

Re: Cannot maintain pool chemistry

How are you testing?

25 gallons of 6% bleach should have taken 15000 gallons of water to over 100ppm concentration. An ordinary DPD test will wash out at levels far less than that and show zero. An OTO test should be very, very dark brown. Strips likely cannot show that high a level. A FAS-DPD test would probably be most accurate. A full compliment of test results could help here, especially CYA (stabilizer) level.
How have you been chlorinating you pool up to now?
How long are you running your filter?

It is avidly possible that your chlorine is being consumed as you put it in. As it does it's job, it goes away. Giving its' life in the line of duty, as it were.

Other potential issues are that your bleach strength could have deteriorated, and be less concentrated than thought, but 25 gallons is still a lot. Even at 1% strength, it should have raised your FC ~~ 10 or 15 or so. As an aside, you may want to confirm that the containers are actually gallons, as Clorox and some others don't use gallon sizes much anymore.

Re: Cannot maintain pool chemistry

First, make sure you aren't using a DPD (shades of red) test kit or strips. Use an OTO chlorine test or a FAS-DPD chlorine test (with extra scoops and look for a flash of pink and add more) to make sure if you have chlorine or not in the pool. You can also get an inexpensive ammonia test kit from a pet/fish/aquarium store. You can also test your Cyanuric Acid (CYA) level to see if it dropped significantly -- if it did, then when the chlorine went to zero, bacteria could have converted some of the CYA into ammonia and depending on how much this can take a lot of chlorine to get rid of.

So getting accurate test results is key here. If you are already using an appropriate chlorine test, then you can do a bucket test to see how much chlorine it will take before the chlorine will start to hold. 1/4 teaspoon of 6% bleach in 2 gallons is 10 ppm FC. You really should have either a Taylor K-2006 (or the equivalent rebranded Leslie's Chlorine Fas-DPD Service Test Kit) or the TF100.

Re: Cannot maintain pool chemistry

Thank you all for your input. I'm using a Taylor K-2005 test kit, with all testing chemicals purchased either this year or last year. I'm using Wal-Mart bleach and it is either the gallon size or 1.4 gallons. It does show 6% and it should be fresh, since I have been buying them out for a while.

My testing results are as follows. Note that I put 3 gallons of bleach in the pool about 2 hours ago.

Re: Cannot maintain pool chemistry

You increase CYA by adding CYA, which you can buy at a pool store, Lowe's or some Walmarts. A good way to add it is to put some in an old sock and put it in the skimmer or hang it in front of a return. It can take a few days to dissolve, and a few more to fully register on the test. Walmart bleach (and all 6% bleach that I'm aware of) is sold in 96oz jugs, not gallons, which can make a difference.

Re: Cannot maintain pool chemistry

I believe that I would hold off. Around 30 gallons of bleach in three days just seems like a lot to me. I am not qualified to know how much ammonia it would take to eat that much chlorine that fast, but like I said, it seems like a lot to me.

As an interim to your FAS-DPD addition, you may be able to find an OTO kit - basic 2-way deal - pretty easily and see if you don't get a reading of "really dark". Leslies has one for under 10 bucks, I think. You might even just get them to do an OTO test on your sample and see for free.

Re: Cannot maintain pool chemistry

Would doing a 3:1 distilled water dilution method work on the DPD test to show FC? Or would it still bleach out? Maybe try that as an option...

Do you happen to know what your CYA level was before? The reason folks are mentioning ammonia is when chlorine levels drop to zero, certain bacteria can convert the CYA into ammonia, dropping the CYA levels to 0 and causing a HUGE chlorine demand. Once bleach is added, you usually see very high CC levels when this has happened. Buying an ammonia test from the petshop can confirm if this is the cause. Either way, it just means alot of bleach is needed to oxidize the ammonia.

On the other hand, if your CYA was very low, it could just be the algae was consuming the chlorine as you added it, and the sunlight was destroying it rapidly as well. However, doing a test after dark would remove sunlight from the equasion.... Does the water look slightly cloudy, just not enough to reach 20-30, (since that's what the tube goes to, it could be somewhere between 0-30).

You don't need to buy an entire K-2006 if you don't need the other tests....if your K2005 is newer and you have enough of the other testing reagents, you can opt to just purchase an FAS-DPD chlorine test separately. Taylor's website sells the individual test, as does TFTestkits, for about $25 plus shipping. You get more reagent with TFtestkits, however.

Re: Cannot maintain pool chemistry

I certainly hope that the chlorine didn't drop to zero and that you had 40 ppm CYA that got converted to ammonia (and other intermediate compounds) from bacteria. If you did, then you would be looking at around 100 ppm FC to get rid of it, but that's roughly the amount you've added so far so perhaps you don't have much further to go. A bucket test, with a proper test kit, will tell you for sure.

Re: Cannot maintain pool chemistry

I think I'll take a water sample to Leslie's tomorrow. That should let me know the true chlorine level, as well as my CYA level. I can get the test kit then as well, and the CYA.

Hi, Dave,

It is not uncommon to get inaccurate testing at a pool store.......hard to believe at first but your own testing will be much more accurate.

The only test kit that lelslie's carries (sometimes) that you should consider is the Taylor K-2006....not the K-2005. Of course, I have an agenda in that I sell a suitable test kit, too, but if you don't purchase mine, the K-2006 is the only one available that will do the testing you need to have done.

Re: Cannot maintain pool chemistry

I am going to purchase the Taylor K-2006 test kit tomorrow. Then I'll be able to test the water myself and see what the true readings are. Also, I will get the CYA from the pool store and try to get a little more balance in the water.